From 59f0c4523fdea865fab7d69d878269992a9d08dd Mon Sep 17 00:00:00 2001 From: Allan Stephens Date: Wed, 21 May 2008 14:52:30 -0700 Subject: [PATCH] tipc: Fix skb_under_panic when configuring TIPC without privileges This patch prevents a TIPC configuration command requiring network administrator privileges from triggering an skbuff underrun if it is issued by a process lacking those privileges. The revised error handling code avoids the use of a potentially uninitialized global variable by transforming the unauthorized command into a new command, then following the standard command processing path to generate the required error message. Signed-off-by: Allan Stephens Signed-off-by: David S. Miller --- include/linux/tipc_config.h | 10 +++++++++- net/tipc/config.c | 6 +++++- net/tipc/netlink.c | 16 +++++++++------- 3 files changed, 23 insertions(+), 9 deletions(-) diff --git a/include/linux/tipc_config.h b/include/linux/tipc_config.h index b0c916d1f375..2bc6fa4adeb5 100644 --- a/include/linux/tipc_config.h +++ b/include/linux/tipc_config.h @@ -2,7 +2,7 @@ * include/linux/tipc_config.h: Include file for TIPC configuration interface * * Copyright (c) 2003-2006, Ericsson AB - * Copyright (c) 2005, Wind River Systems + * Copyright (c) 2005-2007, Wind River Systems * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -135,6 +135,14 @@ #define TIPC_CMD_SET_MAX_SLAVES 0x800A /* tx unsigned, rx none */ #define TIPC_CMD_SET_NETID 0x800B /* tx unsigned, rx none */ +/* + * Reserved commands: + * May not be issued by any process. + * Used internally by TIPC. + */ + +#define TIPC_CMD_NOT_NET_ADMIN 0xC001 /* tx none, rx none */ + /* * TLV types defined for TIPC */ diff --git a/net/tipc/config.c b/net/tipc/config.c index 91d56f8fee9f..16e7cb74969b 100644 --- a/net/tipc/config.c +++ b/net/tipc/config.c @@ -2,7 +2,7 @@ * net/tipc/config.c: TIPC configuration management code * * Copyright (c) 2002-2006, Ericsson AB - * Copyright (c) 2004-2006, Wind River Systems + * Copyright (c) 2004-2007, Wind River Systems * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -602,6 +602,10 @@ struct sk_buff *tipc_cfg_do_cmd(u32 orig_node, u16 cmd, const void *request_area case TIPC_CMD_GET_NETID: rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_net_id); break; + case TIPC_CMD_NOT_NET_ADMIN: + rep_tlv_buf = + tipc_cfg_reply_error_string(TIPC_CFG_NOT_NET_ADMIN); + break; default: rep_tlv_buf = tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED " (unknown command)"); diff --git a/net/tipc/netlink.c b/net/tipc/netlink.c index 6a7f7b4c2595..c387217bb230 100644 --- a/net/tipc/netlink.c +++ b/net/tipc/netlink.c @@ -2,7 +2,7 @@ * net/tipc/netlink.c: TIPC configuration handling * * Copyright (c) 2005-2006, Ericsson AB - * Copyright (c) 2005, Wind River Systems + * Copyright (c) 2005-2007, Wind River Systems * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -45,15 +45,17 @@ static int handle_cmd(struct sk_buff *skb, struct genl_info *info) struct nlmsghdr *req_nlh = info->nlhdr; struct tipc_genlmsghdr *req_userhdr = info->userhdr; int hdr_space = NLMSG_SPACE(GENL_HDRLEN + TIPC_GENL_HDRLEN); + u16 cmd; if ((req_userhdr->cmd & 0xC000) && (!capable(CAP_NET_ADMIN))) - rep_buf = tipc_cfg_reply_error_string(TIPC_CFG_NOT_NET_ADMIN); + cmd = TIPC_CMD_NOT_NET_ADMIN; else - rep_buf = tipc_cfg_do_cmd(req_userhdr->dest, - req_userhdr->cmd, - NLMSG_DATA(req_nlh) + GENL_HDRLEN + TIPC_GENL_HDRLEN, - NLMSG_PAYLOAD(req_nlh, GENL_HDRLEN + TIPC_GENL_HDRLEN), - hdr_space); + cmd = req_userhdr->cmd; + + rep_buf = tipc_cfg_do_cmd(req_userhdr->dest, cmd, + NLMSG_DATA(req_nlh) + GENL_HDRLEN + TIPC_GENL_HDRLEN, + NLMSG_PAYLOAD(req_nlh, GENL_HDRLEN + TIPC_GENL_HDRLEN), + hdr_space); if (rep_buf) { skb_push(rep_buf, hdr_space); -- 2.30.2